Filler composition and method of making



Patented May 24, 1938 FILLER COMPOSITION AND METHOD OF MAKING Andrew Thoma, Cambridge, Mass, assignor, by

mesne assignments, of one-half to North American Holding Corporation, Syracuse, N. Y., a corporation of New York and one-half to Parshad Holding Corporation, Syracuse, N. Y., a corporation of New York No Drawing. Application June 18, 1934, Serial No. 731,217

7 Claims.

This invention relates to an improved filler composition for shoes and to a method of making the same.

In the art of making shoes, even though there are several different types of procedure, there is a common requirement that the space left between the inturned margins of the upper and the inner and outer soles, shall be filled in. In earlier practices of the art it was common to fill this cavity with scraps of leather. This was unsatisfactory, as proven by the universal abandonment of leather as a shoe filling material, and the general substitution of plastic compositions for this purpose. The plastic compositions which have been developed have contained numerous ingredients and have been progressively improved since their first adoption in the art of shoe manufacture. They are, as now provided, especially well adapted for the intended purpose and not only readily conform to the cavity in the shoe during the manufacturing operations of applying them and assembling the other parts of the, shoe thereon, but afford a high degree of satisfaction in the firmness and yet yielding resiliency which they impart to the sole of the finished shoe and whichis so desirable to the wearer during use.

The conditions which lead to a satisfactory shoe filler composition from the standpoint of application to the shoe and from a consideration of its properties in the finished shoe are, however, somewhat different and in some respects opposed to each other. For example, when the composition is being applied to the shoe cavity it is essential that it shall be fluid or freely plastic in order to conform readily to the size and shape of the cavity. It is also important that it shall wet or at least form an intimate contact with the wall surfaces defining the cavity, and preferably that it shall both wet and adhere uniformly and tenaciously to such surfaces. It is also desirable that it shall conform and adhere to the outer sole as the latter is applied over the shoe filler composition, thus enclosing the cavity, and confining the filler therein. But after the outer sole has been thus attached to the shoe and the shoe is finished, it is essential, for the proper satisfactory preservation of the wearing qualities of the shoe that the filler composition shall not readily deform or shift, either spontaneously or to any appreciable degree under the usual temperatures to which it is likely to be exposed or under the weight of the wearer of the shoe. On the other hand, it must not harden nor becomfi brittle.

In obtaining these conditions in t -e filling compositions heretofore prepared there has been a tendency for the preliminary steps of preparation such as heating or subjecting to steam, in order to develop the desired properties of consistency, and spreadability in its application to the shoe cavity) to leave certain of the fluid reagents employed for this purpose in the comminuted solids or body material of the composition. This tends to make the composition heavy and also to promote subsequent reactions, either chemical or physical, resulting in subsequent changes in the consistency and other characteristics of the filler composition as a whole, which are highly undesirable.

It is accordingly an object of this invention to provide an improved filler composition for shoes and a method of making the same which shall not only meet the conditions required for its ready application to the cavities of shoe bottoms and during the subsequent steps of constructing the shoe, fill the cavity between the inner and. outer soles, and adhere to the walls of the shoe cavity, but which will also impart to the bottom of the finished shoe the continued flexibility desired without shifting or losing its shape, and without becoming stiff or brittle with age, either during storage or in long continued use. It is a further object to provide such a consistency in the filler composition, substantially independently of the conditions or properties which may be imparted to the composition during the step of filling the composition into the shoes or the subsequent steps of manufacture, and to assure that the filler in the finished shoe shall promptly acquire and retain a predetermined consistency, resiliency, etc. A further object is to provide a filler having a body material which, after being deposited in the finished shoe, shall be characteristically porous, relatively light in weight, and yet resistant to compacting under the pressure of the foot, resistant or repellent to the absorption of moisture, even though immersed in water, and also resistant to changes of internal density as more fully hereinafter described. A further object of the invention is to cause the filler composition as a whole to acquire a firmness of consistency promptly after its application to the shoe bottom and which is practically unaffected thereafter, as by moisture, dryness, changes in temperature, pressure of the foot, absorption by the adjacent portions of the shoe or progressive changes of setting, resulting in increased hardness, etc. Other objects of the invention will appear from the following disclosure.

As prepared at the present time, the great majority of filler compositions used comprise generically a mixture of comminuted solid or body material, which is porous and elastic, such as ground cork, and an adhesive, but essentially non-hardening and yieldable, resilient binder. These ingredients are thoroughly mixed and provide a composition which, especially by the application of dry heat or steam, develop a softness which permits of a suitable quantity being easily separated from the mass and a plasticity which conduces to the ready molding and spreading of the same into the cavity of the shoe. It also develops adhcsiveness and is capable of sticking to the leather surfaces of the shoe. Upon cooling, it tends to thicken and stiifen and set toa firm consistency but without hardening.

Compositions of this general type are disclosed in certain of my issued Patents (1,032,312; 1,121,- 688; 1,121,689; 1,134,931; 1,136,980; 1,227,696; 1,796,671; 1,841,461; 1,868,927; 1,868,928; 1,900,- 316) in which numerous materials are disclosed and various different functions are served thereby,and also in my copending application Serial No. 629,739, filed August 20, 1932, now Patent 2,056,236, in which a novel type of binder, especially suitable for compo shoes, is described.

The present invention relates to an improvement which is applicable to such compositions as are described in these patents and copending application, in that it incorporates therewith, and especially in a preferred novel relationship to the ingredients above described, a reagent material which serves to preserve the light, porous, resili ent consistency of the comminuted body material both during its preparation, storage and application to the shoe bottom, and also in the finished shoe, during storage and while on sale, and more especially throughout its useful service to the wearer, even though such service be for a long period of time. This reagent material also serves the function,--upon or shortly after its application in the shoe bottom,of increasing the toughness, resiliency, range of elasticity, tensile and compressive strength, resistance to permanent plastic flow, etc., and at the same time permits the composition to acquire the resistance to compo cements, described in the copending application above indicated.

The compositions to which the present invention is applicable characteristically contain resinous acids and/or resinates which, while peculiarly adaptable for shoe filler compositions, manifest a tendency to become fluid under initial conditions of preparing the filler composition and to harden after the composition has been applied and allowed to set in the finished shoe, or both. It is now found, however, that by suitably incorporating with the composition, preferably in extremely finely divided solid condition, a mineral substance containing or analogous to a metallic oxide, typically of the bivalent or trivalent metals (and preferably those which are also white or light colored and light in weight) the composition develops a moist, ropy, stringy consistency or lunginess which does not detract from but in fact facilitates its shaping and adhesive proper ties and at the same time gives the composition greater bodiness and consistency than heretofore. The resulting composition also retains this increased bodying eifect after it has set in the shoe, on cooling and/or drying, or upon setting spontaneously as may also be effected as hereinafter described. Such mineral reagents or com.- pounds include not only the oxide forms of the polyvalent metals, but also the hydroxides, basic carbonates, and other characteristically basic compounds which are substantially non-reactive except within the adhesive component of the mixture. Thus, zinc hydroxide and carbonate are suitable, as well as aluminum oxide, aluminum hydroxide, calcium, barium and strontium oxides, hydroxides, etc, but preferably not acidic or freely soluble salts'of such metals, such as zinc chlo ride, alum, etc., unless they be kept in such small amount and so introduced that their complete combination with the resin or resinate compounds shall be assured. An excess of such soluble and reactive compounds would not only be subject to moisture but upon dissolving might irritate the foot of the wearer of a shoe in which such compound had been incorporated in the filler.

' A preferred mode of incorporating the pulverized mineral reagent material, is by mixing the comminuted solids or body material therewith before adding the viscous, adhesive binding mate-- rial or bond. The comminuted solids or body material may be moistened slightly to facilitate the uniform coating and adhesion of the metallic oxide thereto, but this is not essential, and if done should be restricted as far as possible to prevent absorption of moisture by the body material, which it is an object of this invention to avoid. As will appear hereinafter, if the body material absorbs appreciable moisture, it not only becomes heavy and loses its springy, porous, resilient characteristics, but, after incorporation in the filler composition is effectively sealed against loss of such moisture. At the same time, retained moisture may tend to disintegrate the cork or react'with such components of the surrounding bonding material as are water soluble, with deleterious results. In any case, a water saturated body material is less resilient and elastic than one of porous open construction, and especially when enclosed in a matrix of binder.

The mixing of the body material and oxide may be effected in any usual type of apparatus. The metallic oxide, being much finer than the body material, tends to surround and adhere to the body material, and preferably a sufficient amount of the dust is used to form a substantially continuous coating.

The binder composition, which is usually viscous and may also be appreciably warm to facilitate its fluidity and the mixing of the same, is then added to the dust coated granulated body material and thoroughly mixed, preferably with a turning and lifting movement to keep the mixture open and mixable. Thereupon the binder mixes in between the dust coated granules, forming thin films or an intervening menstruum upon the granules or a more or less continuous matrix between them, depending upon the relative amounts used.

It is found that as one constituent of the binding component of such shoe filler compositions, resinous materials, including both synthetic and natural saponifiable resins, typically rosin, are particularly suitable. It is furthermore discovered that, upon admixture of finely divided mineral materials such as metallic oxides therewith, as above described, such compositions acquire a definite and determinable degree of elasticity, strength and resiliency or toughness therein, (which seems most aptly described as 1unginess) and impart this quality to the resultant characteristics of the composition as a whole.

This will occur if the mineral material is mixed with the fluid resinous material. But it also is effected when the mineral matter is introduced in the form of thin films of dust upon the surfaces of the granulated body material as above described. In the latter case there is a marked tendency for the reaction product, of lungy con.- sistency to adhere directly to the body material although. the remainder of the lungy mass extends into and through the intervening adhesive composition between the granules of body material. Such change in the properties of the resinous matrix is permanent, that is, the lunginess is characteristic of the reaction product or products formed and not primarily due to temperature, solvent actions, moisture or other term porary conditions which are subject to change with changes of atmospheric environment or with age. Such compositions are differentiated from those containing free rosin only or soluble alkali metal resinates in that they are extremely tenacious and also stringy and the strings which they form are long and maintain their elasticity or tenacity through extremes of relative distortion, either alone or in mixtures of which they form a part. They also resist distortion and fiovv, although they are slippery and present little internal friction under the action of a spreading knife, for example. They thus transmit strain from one part of such a mass to another without flowing movement, and such strains as are transmitted encounter increasing resistance with increased distances from their pointsv of origin. The resulting distortion (which may be more or less permanent) is therefore greatly diminished. At the same time the elasticity of the mass is essentially maintained. Hence compositions thus constituted provide a comfortable and elastic cushion not only conforming in shape to the foot of the wearer but yielding resiliently to the constantly varying pressures of his foot and in proportion thereto without shifting, withoutcompacting, and. without becoming hard or brittle.

Accordingly it is found that shoe fillers may be made and their resiliency predetermined and rendered substantially permanent by the employof resinous materials in combination with one or more polyvalent metallic oxides, the reaction products of which serve as a binder in combination with suitable body materials, usually containing ground cork which is. especially well adapted for this purpose. At the same time it is found that they may be temporarily rendered more plastic and even superficially fluid, by moderate heating. as by steam, during the initial application to the shoe cavity. without appreciably aifecting the permanent elasticity and resiliency of the composition, as manifested in the finished shoe, for example, after deposition therein.

As thus mixed the consistency and general properties of the mass do not vary greatly from those described in the patents and application above referred to. and may be shaped into con ve ient loaves, transported and stored convenie tly until ready for use. Upon heating, either indirectly in a steam jacketed kettle or directly by the introduction of live steam. the mass is readily permeated, softened and. rendered plastic and in suitable condition for manipulating and applying to the shoe bot om. A charge may be readily severed or cut from the mass, contacted with the interior of the shoe cavity. spread out to fill and adhere to the walls of the and wiped off, to form a uniform surface even with the irregular boundary margins of the shoe bottom cavity. The spreading knife clears itself freely (especially when the composition contains a fusible lubricant such as petroleum jelly) and the shoe sole, when applied to the exposed surface of the filler charge adheres firmly and uniformly thereto. The bonding component is firmer, tougher and stringier than heretofore while the body material is lighter in weight, more porous, more elastic and hence springier than in former filler compositions.

In a preferred and typical instance of carrying out the invention in actual practice, I take commercial light rosin, in the proportion of fortysix pounds by weight, and heat it either in a steam jacket or open gas fired copper pot, to a tempera ture sufficient to render it uniformly fluid. If lumps are left or if the melted mass congeals by local cooling, heating and stirring are continued until the entire mass is fluid, or the temperature is raised slightly if necessary. To the molten rosinis added two pounds of naphthalene and six pounds of medium, yellow petroleum jelly of greasy, self-sustaining consistency, which melts readily and mixes freely with the melted rosin.

The petroleum jelly, while preferred for certain purposes as disclosed in my copending application and for lubricating the spreading knife as above referred to, need not necessarily be pres.- ent in order to secure the advantages of the present invention. But in that case, (or with the petroleum jelly), it will usually be desirable or necessary to add to the melted rosin a softening fluid, such as soap or soap solution, to emulsify the rosin and produce a softer and more pliable structure in contrast to the hard and brittle struc ture which ordinarily results from the solidification of free rosin. Resinates of the alkali metals, however, may produce such softening effect, in part at least, more especially in the presence of water, as more fully described hereinafter, under which conditions the alkali metal resinates, while strongly adhesive, are of relatively fluid consistency at ordinary temperatures.

The naphthalene makes rosin softer and more fluid and tractable during the mixing operation. and consequently the mixture as a whole is more readily blended. An excessive quantity is to be avoided, however, since it tends to sublime at ordinary temperatures and gives oil a distinc tive odor. Its solvent or softening efiect upon the rosin is also not desirable in the finished filler composition, so that it is preferable to add only so much as may be substantially expelled before or shortly after the filler finally deposited in the bottom of the finished shoe.

The addition of naphthalene has the effect of lowering the melting point of the rosin, so that, for example, even with a relatively small amount of naphthalene the mixture may be rendered much more freely fluid than rosin alone, below the boiling point of water. If used in too large proportions, therefore, its subsequent vaporization will tend to form a charge of filler which will gradually become stiffer and harder than desired.

When the petroleum jelly has been incorporated into the mixture, there may be added a small amount of sulphonated castor oil or soluble oil, which is freely miscible therewith. It may be added in free condition or in the form of a water solution. In the instant eight pounds of a 10% water solution of the soluble oil was employed, and added in amounts with continued agitation of the mixture. If the mixture is hot, the addition of the soluble oil solution causes the mass to foam and it may boil over if care is not observed to add it in sufficiently small amounts and to stir it in thoroughly before the next addition is made. In some instances, to avoid such foaming, it may be desirable to add the soluble oil itself instead of in an aqueous solution. In such cases the smaller volume may require more careful measuring.

Soluble oil, which is sometimes referred to as Turkey red oil or sulphonated castor oil, is characterized by having the characteristic physical properties of oil and by also manifesting solubility or substantially infinite, free miscibility with water. The resulting admixture, whether solution emulsion or 'mechanical mixture, is unique in that it is capable of acting as a common vehicle for the mutual solution or emulsification of oils and aqueous solutions or mixtures or both. Hence it is capable of promoting both physical intimacyof contact and admixture, and any chemical reactions of which the several components of the charge may be capable and of imparting to the product the composite properties of such components severally and of their products of reaction. At this stage also, it is therefore made possible, by the incorporation of the soluble oil, (or thereafter) to add other aqueous solutions or suspensions such as a common soap solution,

dextrine solution etc. For example, six pounds of dextrine may be dissolved by mixing with two and one-half gallons of hot water and the resulting solution added to the above rosin-Vaselinesoluble oil mixture. Like precautions are observed of adding slowly, agitating and avoiding over-heating, as above described in connection with the soluble oil.

During the mixing operation, if the mixture evaporates a considerable amount of the aqueous components, it tends to thicken. To oifset this tendency and overcome the reduction of the workability of the mass which ensues, a water solution of soap may be added to bring the mixture back to the desired consistency, and also to cool the mixture if necessary.

The body material for such binder composition is separately prepared and may, for example, consist of twenty-five pounds of cork, ground to granular size, approximating eight mesh, which is then thoroughly mixed with three pounds of finely powdered Zinc oxide. The cork, being light in weight, has considerable volume and in the aggregate presents a very large surface area. However, the zinc oxide, being extremely finely divided is adequate to coat the cork granules substantially completely so that the mass will have the general appearance of being white, although some of the uncovered surfaces of cork may show through the coating so that the mass appears light brown in color. A larger proportion of zinc oxide could advantageously be employed, but is not necessary for a satisfactory product. The zinc oxide coating adheres firmly to the cork granules, but it may be still more firmly attached thereto by moistening the mass of cork granules with a small amount of soap solution, either before, simultaneously with or after the addition of the pulverized zinc oxide.

The moistening of the zinc coated granules of cork also has the advantage of facilitating the uniform and complete contacting and admixture of the rosin-petroleum jelly-naphthalenesoluble oil and dextrine mixture above described which is next added, in warm, freely fiuid condition, to the mass of zinc oxide-coated cork granules, and the entire mixture mixed and worked together nto a uniform, light, granular, porous,

sticky mass. The charge is then withdrawn, spread into a thick but open, porous-textured sheet and cut into loaves for convenient handling and subsequent use. a

The mass, as thus produced, is characterized by containing granular particles, of comparatively dry cork, severally covered with a thin adherent layer of fine zinc oxide dust. The mass is further characterized by containing between the cork granules arstringy, more or less continuous matrix of adhesive bonding material, not fluid enough to wet and separate the zinc oxide from the cork to form a suspension of the latter, but penetrating through such zinc oxide dust coating in places and effecting direct adhesive contact with the surfaces of the cork granules. The rosin or. resinate component of the binder, and perhaps also the soluble soap component, appear chemically to combine with a part at least of the metallic oxide coating, to form more viscous, stringy, aggregations, which attach themselves to the cork granules and also extend into the matrix between the granules of cork, contributing resiliency and elasticity to the mass as a whole. This stringy, coagulated bonding component may exhibit a tendency to coalesce and separate from the dust coated particles, especially as it is first made and/or in compositions not containing Vaseline. This tendency creates fissures, running throughout the mass and constituting irregular parting planes and channels having a wall of zinc oxide dust-coated particles of cork on one side and stringy coagulated masses of the resinous bonding component on the other, likewise more or less coated with zinc oxide.

If stored in this open, granular condition for a long time, it is found that there is a tendency for the mass to become hard or fset and when this has occurred, it is not practicable to reduce it to a plastic consistency. This is thought to be due to the penetration of moisture and action of the same upon the zinc oxide coatings but, in any event, it may be overcome by the use of petroleum jelly (which covers the granules and/or zinc oxide or closes the fissures) or by slicking over the.

shoes, as more fully set forth and discussed in my copending application referred to above. Likewise, it may be observed that aqueous components, such as'soluble soap, dextrine or other materials which are miscible with or attractive of water, and which are rendered miscible with the rosin and petroleum jelly (or vise versa) by virtue of the addition of the soluble oil, are also effective in the finished product to resist the penetration of various solvents and solvent solutions, such as the organic solvents of compo shoe cements, for example,

When the mass is to be used it may be placed in the usual shoe filling machines and subjected to heat, either from the outside only or from the inside, by injecting live steam into the mass, or both. The latter is especially desirable in compositions not containing petroleum jelly. The

mass as a whole thereupon softens, the voids close up and the bonding component, becoming more fluid, surrounds and wets the zinc oxide coated granules of cork. But there is little tendency for the viscous mass to penetrate into the porous structure of the cork. This may be attributed to both the chemical and physical action of the dust coating. The fine dust coating tends to be liquid repellent but the admixture and reaction of the oxide with the resinous binders which is promoted by the heating or steaming treatment results in forming a viscous mixture of resinates. The latter firmly contact and adhere to the cork surfaces and develop the substantially permanently stringy, water insoluble, resilient, flow-resisting properties characteristic of these compounds and imparts them to the composition as a whole. The mixture is freely spread and molded into the shoe cavity, adheres firmly thereto, is easily smoothed off along the margins while preserving intimate contact and adhesion to the inturned margins of the upper, and firmly adheres to the superposed outer sole. The spreading knife clears freely from the mixture in the spreading and wiping action, and when the margins of the upper require roughening, as with a wire brush, the brush or other instrument used for this purpose does not fill with the filter composition but readily clears and cleans itself during the operation. The composition is likewise resistant to numerous solvents, such as may be encountered in the compo process of making shoes, and is resistant to water, dampness, etc., as finally incorporated in the finished shoe. Moreover, it retains its firm resiliency without becoming stiff and cracking or crumbling, shrinking, or otherwise seriously deformingwhether the shoe be kept in transportation, storage or display for long periods of time, or whether it be worn continuously or at infrequent intervalsand hence subjected to long intervening periods of drying, moisture, etc., depending upon the climate and care or lack of care which it receives, and is nevertheless ready for use and provides a comfortable shoe when wanted.

While, as above described, it is usually preferred to add the dust or comminuted mineral oxide to the granular body material, it is to be understood that it may be added to the binder component directly or to both the granular body material and to the binder component. It may also be added to a previously prepared mixture of body material and binding material. In all of such cases, however, intimate admixture and uniform dispersion of the same through the mass as a whole is desired.

I claim:

1. Method of preparing shoe filler compositions, comprising the step of incorporating comminuted, granular body material with a finely divided mineral compound, and then with a plastic fusible bonding material, and subsequently rendering the mass freely spreadable by the introduction of steam.

2. Method of preparing shoe filler compositions, comprising the steps of coating the granules of a comminuted porous body material with an oxide of a polyvalent metal in finely divided condition and then mixing with an adhesive resinous binding material.

3. Method of preparing shoe filler compositions, comprising the step of mixing comminuted body material with a finely divided zinc oxide and then mixing with an adhesive resinous bonding material.

4. A shoe filler composition comprising a comminuted body material, a finely divided mineral compound distributed primarily upon the surfaces of said body material, and a plastic fusible adhesive bonding material, mingled with the mineral coated granules of body material while leaving the mass as a whole open and porous.

5. A shoe filler composition comprising a comminuted body material, finely divided zinc oxide and a resinous adhesive bonding material.

6. A shoe filler composition comprising a comminuted body material, a finely divided oxide of a polyvalent metal distributed primarily upon the surfaces of said body material, and an adhesive resinous bonding material, mingled with the oxide coated body material.

7. A shoe filler composition comprising a comminuted body material, finely divided zinc oxide distributed primarily upon the surfaces of said body material, and an adhesive bonding material containing an insoluble resinate, mingled with the oxide coated body material.

ANDREW THOMA. 

